The present invention relates to apparatus for dispensing liquid soap, normally in discrete small quantities or charges. In particular, the present invention is an improvement of the discharge assembly disclosed in copending application Ser. No. 680,822, of Antonio Macchi Cassia, entitled "Discharge Assembly for Liquid Soap Dispenser," and assigned to the assignee of the present invention.
The soap dispenser disclosed in the aforementioned patent application is of the type which utilizes a flexible or compressible pump means which defines a discharge chamber for receiving soap from a container through a diaphragm-type check valve. When the pump means, which may include a nipple, is compressed it closes the check valve and forces the soap in the discharge chamber out through a discharge opening. However, the discharge assembly disclosed in the aforementioned copending patent application does not provide means for venting the liquid container so as to ensure rapid equalization of the pressures inside and outside the container to facilitate the flow of liquid soap therefrom.
It is known to vent the liquid soap container in a soap dispenser by providing a separate vent opening in the container, typically at the opposite end thereof from the outlet opening. This type of arrangement is disclosed, for example, in U.S. Pat. Nos. 1,326,880 and 4,345,627. But that type of arrangement is disadvantageous because it complicates the manufacture of the container and provides another opening to the container which might accidentally be prematurely opened, increasing the chance of contamination or loss of the liquid soap before the container has been mounted for dispensing use.
It is also known to provide discharge assemblies for dispensers which include vent means for venting a container through its outlet opening. One such arrangement is disclosed in U.S. Pat. No. 2,605,021, but that device includes a very complicated discharge assembly and utilizes a snorkel tube extending up into the container above the fluid level therein. U.S. Pat. No. 4,120,430 discloses a pump-type dispensing apparatus for a spray bottle or the like, which simply uses a vent hole which provides communication between the pumping apparatus and the interior of the bottle. But that arrangement would be completely unsuitable for an arrangement, such as a liquid soap dispenser, wherein the container is inverted in use with the outlet opening disposed downwardly, since the contents of the bottle would leak through the vent opening.